Control device



CONTROL DEVICE Filed June 30, 1942 2 Sheets-Sheet l l I, 7@ n 5f 47 49 55 Q 4648 .f3 f; 5 5/557 56 4o 5958 52 Snventor,

(Ittorneg.

May 9, 1944. L L. CUNNINGHAM 2,348,454

CONTROL DEVICE Filed June 30, 1942 2 Sheets-Sheet 2 jg k 57 if 55 xm 4,14/ 6 f Uff'. C "HM 2 f Y f FH 64 J if" V` J y 50 pfff 5f E lmnentor,

EW/S L. Cz//Y/Y//YGHAM (Ittorncg Patented May 9, 1944 UNITED S CONTROL DEVICE` Application u'inne 30, 1942, Serial Noo Mailto 1 Claim.,

the operative relation between the condition re-G sponsive means and the controlling means can be varied, as in accordance with the operative position of a device controlling the condition.

Such additional means is an essential element of condition-controlling follow-up systems, lin connection with a typical example of which the device of the present invention will be described in detail hereinafter.

An object of this invention is to provide a device of the character described in the form of a simple, compact, unitary structure wherein the means for varying the relation, or position, of the controlling means with respect to the condition responsive means comprises a single moving part.

Another object is the provision oi a device or the character described wherein the means for positioning the controlling means also serves to support or mount the same.

Another object is the provision of a hollow,

threaded connection for mounting and positioning the controlling means, through which connection the condition responsive moving means extends.

Other objects and advantages of the invention will be found in the description, the drawings, and the appended claim; and for complete unn derstanding of the invention reference may be had to the following detailed description and ac companylng drawings, wherein I' Figure 1 is a side elevation of'a control device embodying my invention;

Figure 2 is an enlarged longitudinal sectional View of the device shown in Fig. l

Figure 3 is a fragmentary transverse section taken along the line 3-3 of Eig. 2, through the subnbase and cover 65;

Figure 4 is a bottom plan of the device shown in Fig. 2, with cover 65 removed; and

Figure 5 is a schematic view of the device illus-- trated in the other iigures, and of an electrically controlled fluid pressure motor, the positioning of which the device is adapted to control.

In the drawings, the numeral il indicates a hollow cylindrical base or support for the device whereby it can be mounted as on a wall l2, a hanged portion of the base being clamped (o1. atomica by a ring i3 to a hanged tting lil threaded in an opening through the wall, such arrangement permitting angular adjustment of the device. Threaded in the upper end of the hollow hase Il is a temperature responsive device, generally indicated at l5, which extends through the opening in wall l, the upper side of which wall may dene a space the temperature of which is to he controlledsuch as, for example, that or the liquid tank or radiator oi a liquid-cooled airplane engine.

The temperature responsive device l5 is of the type disclosed in the oopending application of William A. Ray, Serial No. 441,773, led May 5, i942, and comprises a lower tubular portion i6 within which is an expansible-contractible me taille bellows il. The bottom end of the bellows is secured, as by solder, to a washer I8 which in turn is soldered to the tube I6.; the top end of the bellows being soldered to the head I9 of a movable stem '2G which extends downwardly withn in the bellows and through the washer i8. The upper end of. the tubular portion i6 is closed wall 2l, from which integrally extends a long upper tubular portion 22. This portion has a relatively thick wall, the outer surface of which is machined to provide a plurality of spaced fins 23. Surrounding the portion 22 and sealingly secured at its ends thereto, as by solder, is a tube 2t. As illustrated, the ns 23 .are formed as a continuous helix so that the space between the tube 2t and. the portion 22 is divided by the fins into an elongated helical passage which communicates at its lower end,k by an opening 25 through the wall il; with the space within the lower tubular portion it around the bellows il .and head lil; this space and the helical passage being charged with a thermostatic liquid. The iins 23 eect good transfer of heat to the liquid both from the outside and from the central passageway of the thermostatic unit constituted by the upper portion 22, openings 2t in the lower end of this unit permitting huid circulation through its central passageway. lt will be understood that all parts of the temperature responsive device l5 are of metals having good heat-conducting properties, such as copper or of the temperature responsive device i5.

on a bracket 34, secured to the disk 3|, by a yieldable metal strip or blade 35 which is so flexed as to urge the free end of the arm upwardly. As is best seen in Fig. 3, the arm 33 carries cen-y trally of its free end a double-faced main contact 36 and a pair of auxiliary contacts 31 and 36, located on either side of the main contact. Cooperable with the lower face of the main contact is a relatively fixed contact 39 mounted on one end of an arm 49 which is supported at its other end by a post 4| (Fig. 2) the arm being flexed downwardly into engagement with the head or a screw 42 extending through an opening in the arm and threaded in another post 43 for vertical' adjustment of the contact-carrying end of the arm; both of lthe posts 4| and 43 extending through an elongated opening 44 (Fig. 4) in the arm 33 and being secured to the disk 3|. Cooperable with the upper face `of the main contact 36 is a contact screw 45 xedly secured in the disk 3|. Cooperable with the upper auxiliary contact 39 (Fig. 3) is a relatively xed contact 46 carried `by an arm 41 (bent edgewise as shown in Fig. 4) which is adjustably supported by a pair of posts 48 and 49 in a manner similar to that in which arm 49 is supported. The other, or lower, auxiliary contact 31 cooperates with a contact 59 carried by an arm 5| which also is adjustably supported by another pair oi posts 62 and 53 in a manner similar to that in which arm 46 is supported except that in this instance the arm is upwardly flexed and is adjusted `by a backing-oil screw 54 threaded in post 53. It will be noted that the arm 41 can yield when up- -ward pressure is applied to contact 46, and that arm 5| is similarly yieldable in a downward direction. It will also be noted that the pairs of main contacts 39, 45 and 36, 39 are spaced farther apart than are the corresponding pairs of auxiliary contacts 39, 46 and 31, 59.

The contacts 46 and 50 are electrically connected, respectively, through their arms 41 and 5| and wires 55 and 56 to one end of resistance elements 51 and 69 (Eig. 4) which rest in an annular recess 59 formed in the undersurface of the sub-base 3|); the other ends of the resistance elements being connected to wires 69 and 6| which are spliced to wires 62 and 63 which extend from the supports of the main fixed-contacts 45 and 39, each respectively. The main and auxiliary movable-contacts 36, 31 and 38 are electrically connected through arm 33, blade 35 and bracket 34 to another wire 64. The switching mechanism is provided with a cover 65 which is attached to the sub-base 3| by screws 66 threaded in the outer ends of the studs 32.

For actuating the switch arm 33, a connection is provided between it and the movable stem 29 This connection comprises a rod having a head 1|A of a size to slide in a bore formed in the bottom end of the stern 2|). The rod is restrained from movement relative to the stem by a compression spring 12, which holds the underside of the rod head 1| in rrn engagement with a bushing 13 surrounding the upper portion of the rod and secured in the mouth of the stem bore by solder. The spring 12 serves as a strain-1elease and is of such stiffness that relative movement of the rod and stem is permitted only in the event that the liquid pressure applied to the stern head I9 (due to temperature rise at the thermostatic unit 22) becomes excessive, and does not occurduring the normal operation oi' the switching mecha nism, Urging the stem assembly upward, is a spring 14 surrounding the stem and rod and compressed between the stem headI I9 and the in sulating disk 3|. The lower end portion of the rod 19 extends freely through a central opening in the insulating disk 3| so that its extremity engages an adjusting screw 16 threaded in the movable contact arm 33, which screw after final adjustment is locked in position by solder.

Adjustably mounting the sub-base 39. and the controlling means associated therewith, on the cylindrical base |I is a sleeve 16 which is internally screw-threaded to cooperate with threads formed on the periphery of the base; the sleeve extending through the central aperture of the sub-base and having a flanged bottom portion 11 which is a tree sliding ilt in a recess formed by the upper surface of the insulating disk 3| and an undercut in the inner edge oi the subfbase. To prevent rotation of the sub-base with respect to the base when sleeve 16 is turned, a plurality of guide pins 19 are provided which are fixed in the disk 3| and slide in bores 19 formed in the bottom of base II. For turning the sleeve 16, a handle 89 is provided which is clamped to the sleeve a strap 9|. By this arrangement, it will be se that when handle 99 is operated, the switching mechanism is adjusted with respect to the actuating rod 19; the adjusting means also serving as the sole support for the switching mechanism. For indicating the setting of the switching mechanism, there is provided an indicator 92, attached by a strap 93 to the sleeve 16, which cooperates with temperature graduations 94 (Fig. 1) inscribed on the periphery of the sub-base.

Referring now to Fig. 5 of the drawings, the operation oi the device illustrated in Figs. 1-4 will be described in connection with the control of a four-way electrically operated valve which in turn controls the operation, or positioning, of a fluid pressure motor, between which motor and the control device a follow-up connection is provided whereby the movable element of the` motor is positioned in accordance with the temperature at the thermal unit of the control device.` In the schematic showir g of Fig. 5, the parts of the control device have been assigned reference numerals which are the same as those of the corresponding parts of the structure shown in the other iigures. For the sake of simplicity, the sleeve 16, whereby the switching mechanism is moved with respect to the temperature responsive actuating means, has been omitted; the insulating disk 3| being merely represented as slidable within a pair of fixed walls 99.

The four-way valve, schematically shown, may be of the type disclosed in the copending application of William A. Ray, Serial No. 447,228, tiled June 16, i942, and comprises four independent electroniagnetically-operated valve units 9|, 92, 93 and 94. These units are of like construction and each comprises an electromagnet 96 and a disk-shaped armature-closure-member 96 which is spring-biased into engagement with its seat 91 and attractable to open position upon energizetion of the electromagnet. The inlets (or space above the closure members) of the valve units 9| and 93 are connected together, and to a source trical ground return is provided for eachvalve unit, as indicated. It will be seen that when valve units 9| and 94 are operated byconnecting a source of electrical energy to wire |09, pressure fluid can flow through unit 9| to the chamber |0| of the motor, the fluid in the other chamber |04 exhausting through valve unit 94; the result being that the piston is movedin a right-hand direction. Likewise, when the source of energy is connected to wire |06, the other valve umts 92 and 93 are operated and pressure iluid flows to chamber 04 and exhausts from chamber 0|; the piston moving in a left-hand direction.

Extending from the motor piston |02 is a stem which is connected to, operate means (not shown) for controlling the temperature of the space wherein the thermostatic unit 22 is located; such means being, for example, when the thermostatic unit is inthe liquid tank or radiator ofa liquid-cooled airplane engine (as was mentioned hereinbefore) the flaps or vanos which must be positioned to control air now to the radiator. The piston stem ||0 isalso con-- nected, through a bell-crank and a link ||/2, to the movable insulating plate 3|, so that movement of the piston effects corresponding movement of the switching mechanism with respect -to the switch-actuating rod |0.-

'I'he operation of the system shown in Fig. 5 is as follows: If the temperaturerat the thermostatic unit 22 rises, the resultant expansion of the liquid forces the bellowshead |9 downward, therebyv through rod l0' effecting downward movement of switch'arm 33 and engagement of the auxiliary contact 3l with contact 50. Current now flows from the source ||3,

through the switch-arm 93, contacts 31 and 50,

resistance unit a58, and wires 63, |00, |08` to the electromagnets of valve units 9| and 94. Due to the resistance 53, the flow of current is not now suincient to operate the valve units. Continued downward movement of the switch arm, however, eiects engagement of the maincontacts 35 and 39 (the supporting arm of contact 50 yielding in this movement) and theA current is now by-passed around the resistance 59 so that the valve units 9| and 94 are operated. The resultant movement of the piston stem ||0 in a right-hand direction eiects (through the followup connection) downward movement of disk 3| so that the main contacts 36 and 39 are immediately disengaged. However, the current still owing (through contacts 31 and 50) to the valve units through the resistance 58 is sumcient to Imaintain the armature-closure-members in their attracted, or open, position; it being a well'- known fact that a smaller amount of electrical energy is required to hold an armature in at tracted position than is required to move it to that position through space, due to the change in reluctance of the magnetic circuit. The conditions are therefore such that the piston continues to move until disengagement of contacts venting relative angular movement 31 and 50 is effected, whereupon the valve units 9| and 94 close, and, since the other valve units are also closed, the piston remains in its moved positionthe air ilaps of the airplane engine being held in a somewhat wider-open position.

'I'he sequential-contact and resistance arrangement thus eilects a positive differential of operation which reduces the frequency of operation of the valve units necessary to produce a predetermined change in position of the piston; another beneficial result oi this arrangement being the substantial elimination of arcing at the contacts due to fluttering This feature is disclosed in U. S. Patent No. 2,237,578 granted April 8, 1941 to William A. Ray.

Should the temperature continue to rise, the above-described operation is repeated, the movement of the piston being checked after it has progressed still farther in a right-hand direction; the switch disk 3| then being in a correspondingly lower position. If the temperature at the thermostatic unit now falls, the resultant upward movement of rod 'l0 effects, first, en gagement of the upper auxiliary contact 39 the yieldably-mounted contact 46, and thm, engagement of the main contacts 36 and 45 the contact arm, due to the bias provided by the hinge blade 35, following the rod l0); the other pair of valve units 92 and 93 accordingly being operated. Pressure fluid now flows to the motor chamber |04 through unit 93, and exhausts from chamber |0| through unit 92; the piston therefore moving in a left-hand direction so that the switch disk 3| is raised, through the follow-up connection, to check the piston movement; the desired differential of operation now being effect` ed by the resistance 5l. While I have herein shown and described a specific embodiment of my invention, I wish it to be understood that modifications may be made withoutdeparting from the spirit of the invention; such as, for example, the substitution for the switching mech anism of pilot-valve means for directly controlling a fluid pressure motor. I intend therefore to be limited only by the scope of the appended claim. I claim as my invention:

In a control device: a relatively xed base; a sub-base; a threaded sleeve interconnecting said bases and rotatable to vary the relative position of the bases along the axis of the sleeve;

said sleeve being internally threaded at one end to cooperate with an externally-threaded portion of said fixed base and having at its other end an outwardly-extending lateral a'nge, providing a surface of relatively large area, rotatable in a recess in said sub-base; means for preof the bases when said sleeve is rotated, comprising a pin secured to one of the bases and slidable in an opening in the other of the bases, the axis of said pin being parallel to the axis of relative movement of the bases said bases being free from engagement with each other sthat said ange and said pin serve as the sole support for said sub-base; means movable substantially along the axis of said sleeve in response to change in a condition and so mounted on said fixed base that a movable portion thereof extends within the sleeve toward said sub-base; and means mounted on the sub-base for controlling said condition and operatively engageable by said portion.

L. CUNNING. 

